1. Field of the Invention
The present invention relates to the use of waste heat of a fuel cell.
2. Description of the Related Art
One proposed technique adopted to start the operation of a fuel cell in the low-temperature environment triggers specific operation where the fuel cell is operated to generate electric power at a lower efficiency than the normal operation (hereafter this specific operation is referred to as “low-efficiency operation”) to increase a heat loss (waste heat) of the fuel cell and warm up the fuel cell with the waste heat. Another proposed technique triggers the low-efficiency operation in the state where electric power is supplied from the fuel cell to a load connected with the fuel cell. The proposed technique may be applied to, for example, an electric vehicle equipped with a fuel cell to initiate the low-efficiency operation immediately after a start of the electric vehicle, enable the electric vehicle to start driving at the timing when the temperature of the fuel cell reaches or exceeds a preset temperature, and continue warming up the fuel cell to a warm-up termination temperature while driving the electric vehicle.
There is still room for improvement of the output response and the heat generation response during the low-efficiency operation performed with supply of electric power to the load.